1. Field Of The Invention
The present invention pertains to a multifunctional filtration apparatus for use in the laboratory for chemical and biological testing including the high speed transfer, filtration and treatment of samples containing filtrable substances. More particularly the invention pertains to a device for transferring and collecting filtrable substances on a filter medium utilizing a vacuum and a first manifold to transfer single or multiple samples from test tubes or micro sample plates to a separation chamber and employing the first manifold to separate the liquid and gaseous components of the transferred fluid containing filterable substances before separating the liquid and filterable substances by utilizing the filter medium and a second manifold. The first manifold and separation chamber are disposed on one side of the filter medium and the second manifold is disposed on the other side of the filter medium.
The invention is applicable to all types of filter mediums such as nitrocellulose, paper, nylon and other aerophobic filter mediums including biological membranes and to biological testing for which automated handling was not heretofore possible due to problems of rupturing the filter medium or membrane when the filter medium or membrane was exposed to air or other gases under pressure. The invention allows automation to be used in test procedures which heretofore could not accommodate the drawing of air into the filterable substances or filter medium due to the introduction of inaccurate results or the rupture of the filter medium caused by the entrainment of such air into the filter medium or filterable substances. The invention is able to handle any type of filter medium as well as air sensitive filtered materials captured in the filter by employing automated filtering techniques to replace the heretofore tedious manual operations where vacuum could not be used due to the aerophobic nature of the filter medium which would result in breaking, tearing, rupturing or contamination of the filter medium with air or other gases.
The invention more particularly pertains to a device for the automated transfer and separation of liquid, gaseous components and filterable substances by the utilization of the filter medium as a means for capturing the filterable substances while utilizing a first manifold to transfer and remove gaseous components from the transferred fluids in the separation chamber and utilizing the second manifold to remove liquids and filter the filterable substances on the filter medium. The invention is applicable to all types of laboratory and biological testing and filtering applications including the use of standard biological sample plates which include individual sample wells having volumes of around 0.5 ml for transferring the 0.5 ml sample, separation of the liquid and gas components from the transferred fluids and subsequently filtering the sample through either a filter or another micro filter plate with nitrocellulose filter bottoms by making slight modifications of the layered housing to provide for the separation of the liquid, particulate and gaseous materials utilizing the combination of a first manifold, second manifold and separation chamber.
2. Description Of The Prior Art
The prior art includes many different types of apparatus for filtering and transferring fluids and liquids. Many of the prior art devices for the rapid transfer of fluids utilize a vacuum source and a manifold to assist in the rapid transfer of fluids. Some of the prior art devices utilize two manifolds but none of the known prior art devices employ a first manifold and a separation chamber disposed on one side of a filter medium for transferring samples and then separating the air or the gaseous components of a transferred fluid from the liquid components of the transferred fluid before separating the liquid and solid or semi solid filterable substances by filtration through a filter medium.
In addition none of the known prior art devices provides a multifunctional filtration apparatus which is capable of high speed precision filtering of any fluid containing a filtrable substance through any type of filter medium including nitrocellulose, nylon or biological membranes which are aerophobic and which will not allow air to pass through the filter medium. None of known prior art provides a multifunctional filtration apparatus which allows the quick modification of the filtration apparatus from an aerophobic to an aerophyllic filter medium and from chemical to biological applications and for accommodating biological sample plates with nitrocellulose filter bottoms by substituting layers in the multilayered multifunctional filtration apparatus.
The most pertinent known prior art for filtering fluids is the Bertoncini, et al. U.S. Pat. No. 4,787,988. This prior art patent employs a first manifold, filter medium and a second manifold but does not employ a separation chamber and does not provide for the automated high speed transfer of filterable substances from one group of containers to another. U.S. Pat. No. 4,787,988 further requires test tubes to be manually placed in the device before the layers are put in place including the filter medium layer before the entire device is manually turned over and a vacuum applied to draw the liquid and filterable material in the liquid through the filter medium.
Bertoncini, et al. U.S. Pat. No. 4,787,988 unlike the present invention does not provide for the automated transfer of fluids from test tubes to a separation chamber to separate liquid and gaseous components before filtration. In addition U.S. Pat. No. 4,787,988 is not multifunctional since it is not suited for the filtration and handling of fluids through aerophobic filter membranes or mediums such as nitrocellulose since no separation chamber is provided between the first and second manifolds. In addition the first and second manifolds are not utilized in combination with one another to transfer fluids from a remote group of test tubes to the filter medium and thereafter provide for the separation of the gaseous and liquid components before filtration through a filter medium.
Other prior art such as Gruenstein, et al. U.S. Pat. No. 4,649,967 provides for the multiple transfer of fluids from one set of test tubes to another set of test tubes utilizing a vacuum and a manifold and a valve. Gruenstein '967 does not filter the transferred fluids and does not have a second manifold or a separation chamber. U.S. Pat. No. 4,649,967 merely provides for the transfer of fluids from one group of containers to a second group of containers. U.S. Pat. No. 4,649,967 is not suitable for nitrocellulose filter paper or filter mediums which are aerophobic and as such would not allow air to pass through a filter medium or filter membrane.
Aerophobic filter mediums or membranes such as nitrocellulose which do not allow air to pass through such as is used in biological testing where the addition of air under a vacuum to the filter results in damage to the filter medium or causes errors in the test results due to the reaction of air with the sample has heretofore required the manual transfer of fluids to a device such as disclosed in Lombardy U.S. Pat. No. 4,828,801. In such aerophobic filter mediums liquids containing filterable materials are introduced manually to either drain through the nitrocellulose filter medium or be drawn through by means of a vacuum on only one side of the filter medium to allow the vacuum to speed up the filtration process. A similar device is shown in Levin U.S. Pat. No. 4,978,507 which similarly provides for the manual loading of each of the samples to a membrane or nitrocellulose sheet along with the utilization of a manifold and vacuum only on one side of the filter for drawing filtrable mediums through the nitrocellulose filter or membrane which is not pervious to gases. In such devices the step of transferring the samples has heretofore been accomplished manually and not accomplished by the automated transfer of fluids with a vacuum.
Other prior art patents pertaining to multi well apparatus for biological and biochemical analysis generally provide a manifold on the bottom side of the filter medium to draw liquids containing filtrable matter through the filter medium after manually filling the wells. In all such biological applications cross-contamination between the various sample wells is prevented by clamping the various layers together with a filter medium or membrane disposed between the layers. In all such known prior art filterable fluids must be manually transferred or loaded into the wells. Such prior art includes Bowers, et al. U.S. Pat. No. 5,108,704; Mathus, et al. U.S. Pat. No. 4,927,604; Clark, et al. U.S. Pat. No. 4,902,481; and Schuette U.S. Pat. No. 5,108,603. In all of these prior art examples the fluids containing filtrable substances are manually loaded in the micro sample plate or test tubes before a vacuum is applied to draw the filtrate component of the fluid through the filter medium. In all such applications the automated transfer of fluids is lacking as well as the utilization of a separation chamber to provide for the separation of liquid from gaseous components from the transferred fluids before filtration.
In all known prior art, unlike the invention, washing and subsequent reagent addition steps are again accomplished manually. In the known prior art pertaining specifically to nitrocellulose and aerophobic filter mediums such as inter alia Bowers, et al. U.S. Pat. No. 5,108,704, Schuette, U.S. Pat. No. 5,108,603 and Levin, U.S. Pat. No. 4,978,507 the tops of the wells are left open to allow gaseous components of a fluid to escape to the atmosphere instead of being captured and removed by the first manifold. This of course limits the prior art filter systems since a rapid transfer of fluids is not possible since all transfers and addition of wash solutions and reagents must be made manually into the sample wells of the prior art apparatus or into the openings of the wells of micro sample plates which prevent the high speed washing or addition of solvents or reaction chemicals.
The invention in contrast to the prior art provides for the high speed transfer of fluids, washing as well as the addition of reaction reagents by the utilization of a combination of a separation chamber and a first manifold located on one side of the filter medium and a second manifold located on the other side of the filter medium. With this arrangement samples can be individually and quickly transferred from a number of test tubes, or wells of a micro sample plate or containers quickly and in a single step without cross-contamination and thereafter filtered, washed and reagent materials added all without the numerous manual steps heretofore required in the prior art. The invention is also applicable to all types of filter mediums whether air impervious or not by the utilization of the separation chamber to separate and provide for the removal of gaseous components from the liquid component of introduced fluids before the solid or filtrable components are removed by the filter medium through the activation of the second manifold.
The features of the invention allows the invention to be configured in a number of different arrangements to allow the multifunctional filtration apparatus to be used for a number of different types of filtering procedures and applications in which fluids are individually removed, transferred and the components separated before filtration through any number of different types of filter mediums. These aspects of the invention also allow for the automated and controlled addition and collection of wash fluids or reagents to provide for the washing or further reacting or other processing steps which in the prior art required a number of separate manual and tedious steps that have been obviated by the novel multifiltration apparatus of the invention.
The invention in further contrast to the prior art can be configured in a number of different arrangements to allow any type and quantity of filtrable materials to be transferred to a separation chamber and the liquid and gaseous components separated before separation of the liquid and filterable components by filtration followed by subsequent washing and reagent addition operations by the use of high speed vacuum techniques. The invention further allows for the use of all types of filter mediums whether or not they are gas impervious so that gases can be removed before filtration in order to prevent the air or gases from destroying, deforming or otherwise interfering or reacting with the filter medium or filtered materials.